The Database of Interacting Proteins (DIP) is the original and one of the most extensive databases of information on interacting proteins. It was founded on the assumption that macromoleQular interactions are at the basis of all biomedical science, and that researchers in many branches of biology and medicine can benefit from access to an accurate repository of what is known of protein interactions. To continue its expansion, DIP will adopt a procedure of direct deposition of experimental data by primary authors. Accuracy of interaction data being essential, methods for the assessment of data quality will be extended and applied to DIP, to define a Core set of highly reliable interaction data. The Core interactions will permit construction of networks of interacting proteins, useful to cell and systems biologists. From its inception, DIP has been guided by a program of research into methods for extracting knowledge of networks from genomic and proteomic data. This research emphasis will be will be deepened by introducing new methods for extraction of information on protein networks from genomic and proteomic data, including logical triplet analysis of genomic and microarray data. LiveDIP is the extension of DIP that concentrates on the interactions among proteins in defined states. A second extension of DIP, ProLinks, catalogs functional linkages between pairs of proteins inferred from genomic and proteomic data; it identifies pathways and complexes, and will serve as a feeder to DIP, as its inferred linkages are validated as true interactions. To provide faster and more reliable access to DIP, its IT infrastructure will be upgraded.